Constitution is the aggregate of and individual’s stable physical and functional characteristics. The importance in Chinese medicine lies in its diagnostic value.

This chapter discusses the concept of constitution, various schemes that have been posited for identifying constitutional types, the various factors influencing the development of constitution, and the ways in which constitution theory is applied in practice.

Overview of Constitution

• The Concept of Constitution
• Constitutional Types
• Formation of Constitution
• Application of Constitution Theory

The Concept of Constitution

What Is Constitution?

Constitution is the aggregate of stable physical and functional characteristics of an individual. These include:

• Physical characteristics, such as shape and size of body, the firmness of the flesh, color of skin, and complexion.
• Functional characteristics, such as physical strength (muscle power) or digestive efficiency.
• Mental characteristics, such as aggressive or quiet disposition.

Individuals not suffering from illness, i.e., more or less healthy individuals, differ in these constitutional characteristics.

These various characteristics determine a patient’s susceptibility to certain pathological conditions, such as yáng vacuity, yīn vacuity, phlegm-damp, damp-heat, blood stasis, or depressed qì. In fact, these tendencies provide labels for constitutional types in most categorization schemes.

How is Constitution Determined?

Constitution is determined by congenital factors and is influenced by factors after birth such as development stage, diet, lifestyle, and illness. An individual’s constitution is not something immutable from birth. It can change over the course of life. However, it does not change from day to day.

• Congenital factors: Many of our basic characteristics such as body shape and size and physical strength are inherited from our parents.
• Stage of life: Constitution can vary from one stage of life to another. Some children have weak constitutions that make them prone to illness. The natural decline in advancing years is reflected in a decline of kidney essence and a weakening of yīn and/or yáng.
• Diet and lifestyle: Some characteristics, especially functional characteristics, can change as a result of dietary and lifestyle habits, e.g., obesity resulting from overconsumption of fatty food and from lack of exercise.
• Illness: Severe or prolonged illness can affect an individual’s constitution. For example, it can result in poor appetite and chronic underweight.

How is Constitution Analyzed?

Chinese medicine has produced different methods for analyzing constitution. These are based on the general parameters such as qì, and blood, and especially yīn and yáng. Differences in characteristics of more or less healthy individuals can be understood in terms of variation between individuals in the internal balance of these basic facets of health.

What is the Significance of Constitution?

The significance of the Chinese medical understanding of constitution lies in the ability to relate outwardly visible characteristics to functional characteristics. From the first encounter with a patient, the practitioner sees the size and shape of the body, firmness of the flesh, and color of the skin. These outward constitutional indices tell the practitioner what functional strengths and weaknesses the patient is likely to have, what problems the patient is likely to be susceptible to, and how the patient’s pathological conditions are likely to develop.

Chinese medicine understands illness to be caused by external causes and internal imbalances. These two factors are not entirely separate, since the body’s internal balance determines each individual’s reaction to external causes of disease. Constitutional imbalances thus play a decisive role in the development of illness and are a major consideration in ensuring successful treatment.

Constitutional Types

Chinese medical scholars have produced different schemes for analyzing constitution. The ones presented below are the threefold, fourfold, and fivefold yīn-yáng classifications, a fivefold classification based on the five phases, and a modern sixfold classification.

Threefold Yīn-Yáng Classification

The simplest method of analyzing constitution is the one based on yīn and yáng. This scheme is the one most widely presented in the constitution section of standard modern textbooks. For these reasons, it is the one most appropriate for beginners.

According to this scheme, there are three basic constitutions: yīn-yáng harmony constitution; yáng-biased constitution; and yīn-biased constitution.

Yīn-Yáng Harmony (Normal) Constitution

A constitution in which yīn and yáng are in harmony, that is, in balance, is the healthiest constitution. This is called a yīn-yáng harmony constitution (阴阳平和质 yīn yáng píng hé zhì).

• Body: People with such a constitution have a firm body and are neither excessively thin nor excessively fat.
• Complexion: Their complexions may vary in color, but they always have a bright, healthy coloring and a healthy sheen.
• Eyes: Their eyes are bright and spirited.
• Disposition: They have an amiable and cheerful disposition.
• Appetite: They may have a moderate appetite.
• Stool and urine: They have well-regulated urine and stool.
• Adaptability: They adapt easily to changes in the environment.
• Sleep and rest: They sleep well and regain their vigor after rest.
• Vigor: They are blessed with mental vigor and have a great capacity for work.
• Susceptibility to illness: They do not easily contract external evils and rarely fall ill. When they do succumb to illness, they recover spontaneously or respond well to treatment. Provided they do not suffer major physical accidents or contract any major epidemics, they often continue to enjoy good health into old age and have a long lifespan.

Yáng-Biased Constitution

The yáng-biased constitution (偏阳质 piān yáng zhì), which can also be called a yīn-vacuity constitution, is when one in which yáng is stronger than yīn. It manifests in heat, activity, and in some cases dryness.

Body: People with such a constitution tend to have thin, but firm bodies. Their complexion tends to be either red and dry or sallow and swarthy and sometimes slightly oily.

Disposition: They tend to be extroverted and active but also rash, impatient, and lacking in self-control.

Appetite: They tend to have a large appetite without growing fat.

Heat: They tend to dislike heat, and a have a preference for cold. In some cases, their body temperature is slightly high.

Sweating: They tend to sweat a lot and have a high fluid intake.

Activity: They are energetic and agile; they have quick reactions and a strong libido.

Susceptibility to illness:

• People with a yáng-biased constitution are especially susceptible to yáng evils such as wind, summerheat, and heat. These tend to manifest classically as heat patterns and repletion patterns and to transform into dryness and damage yīn.
• They are also susceptible to boils and other sores caused by heat toxin.
• As regards internal damage, they are prone to fire effulgence and hyperactivity of yáng, sometimes with yīn vacuity. They are also prone to dizziness, headache, heart palpitation, insomnia, and bleeding.
• People with yáng-biased constitutions have hyperactive yáng qì, they are active and rarely quiet, and they suffer from heat that damages yīn. When they are overworked physically or mentally or indulge in sex too often, their yīn aspect is easily damaged, giving rise to pathological conditions of hyperactive yáng, yīn vacuity, and phlegm-fire.

Yīn-Biased Constitution

The yīn-biased constitution (偏阴质 piān yīn zhì), which can also be called a yáng-vacuity constitution, is one in which yīn is stronger than yáng. It is characterized by cold, stillness, and dampness.

Body: People with such a constitution are usually fat and weak. Their facial complexion tends to be white and lusterless. This is the familiar white flabby type.

Disposition: They are often introverted in disposition, like quietude, are inactive, and tire easily. In some cases, they tend to be timorous and lack courage.

Appetite: They tend to have a small appetite, but still tend to be fat.

Heat: They usually fear cold, like warmth, and tend to have a low body temperature. They have little physical vigor and are often slow in their movements and reactions.

Susceptibility to illness

• The yīn-biased constitution is especially vulnerable to cold and damp evils.
• After contraction of evils, conditions tend to transform toward cold. When they suffer from exterior patterns, these tend not to be characterized by heat effusion. External evils easily pass to the interior or strike the bowels and viscera directly.
• They are vulnerable to chilblains and frostbite.
• As regards internal damage and miscellaneous diseases, people with yīn-biased constitutions have weak yáng qì, so they are susceptible to insufficiency of yáng qì and yīn exuberance. They tend to have poor bowel and visceral function and hence are prone to water-damp arising internally, cold-damp, phlegm-rheum, and blood stasis.

Fourfold Yīn-Yáng Classifications

Líng Shū Fourfold Classification

The Líng Shū (Chapter 67, Using Needles) describes four constitutional types—double yáng, double yáng with yīn, copious yīn and scant yáng, and yīn-yáng harmony type—to explain different reactions with regard to obtaining qì (eliciting sensations at or near the needle insertion site). The main statements in Líng Shū (67) are as follows:

• People with double yáng (重阳之人 chóng yáng zhī rén): Their spirit is easily stirred and their qì moves easily (其神易动, 其气易往 qí shén yì dòng, qí qì yì wǎng). Double yang persons are fervid and lofty. They speak well and fast. When walking, they raise their feet high. The qi they store in their heart and lung have a surplus. Their yang qi flows smoothly; it abounds and effuses. Hence when their spirit is excited, their qi will move even before [the needle is inserted] (熇熇高高，言语善疾，举足善高，心肺之藏气有余，阳气滑盛而扬，故神动而气先行 hè hè gāo gāo, yán yǔ shàn jí, jǔ zú shàn gāo, xīn fèi zhī cáng qì yǒu yú, yáng qì huá shèng ér yáng, gù shén dòng ér qì xiān xíng).
• People with double yáng with yīn (重阳有阴之人 chóng yáng yǒu yīn zhī rén): Their yīn and yáng separate and unite with difficulty, so their spirit does not move before [the needle is inserted] (阴阳离合难, 故其神不能先行 yīn yáng lí hé nán, gù qí shén bù néng xiān xíng).
• People with copious yīn and scant yáng (阴多而阳少之人 yīn duō yáng ér shǎo zhī rén): Their yīn qì is sunken and their yáng qì is floating (阴气沉而阳气浮 yīn qì chén ér yáng qì fú). So, when the needle is withdrawn, the qi follows it, thus moving by itself (故针已出，气乃随其后，故独行也 gù zhēn yǐ chū, qì nǎi suí qí hòu, gù dú xíng yě).
• People with yīn-yáng harmony (阴阳和调之人 yīn yáng hé tiáo zhī rén): When yin and yang are in harmony, blood and qì are supple and moist, and uninhibited, so that when the needle goes in, qi comes out, the two confronting each other immediately (阴阳和调，而血气淖泽滑利，故针入而气出，疾而相逢也 yīn yáng tiáo hé, ér xuè qì nào zé huá lì, gù zhēn rù ér qì chū, jí ér xiāng fēng).

The text of Líng Shū (67) mentions no double yīn type, which, if it did, would make five.

Zhāng Xū-Gǔ’s Fourfold Classification

Zhāng Xū-Gǔ (张虚谷) in his Yī Mén Bàng Hè (医门棒喝 Call to Awakening in Medicine) offers a fourfold categorization of constitutions that bears certain similarities to that of Líng Shū (67). This scheme is not widely presented in modern basic theory textbooks, probably owing to lack of detail. It does, however, reflect two established axioms: Obese people tend to have copious phlegm (tendency to wind-stroke) and thin people tend to have copious fire. This classification also has the merit that its constitution marked by exuberance of both yīn and yáng explains anomalies that appear in the application of the a threefold classification.

Yáng exuberance and yīn vacuity: Thin body, somber-white complexion, insufficiency of center qì, and a stringlike pulse, bright eyes, no great appetite, but able to work. A person with this constitution has a tendency toward fire diseases.

Exuberance of both yīn and yáng: Fleshy body, exuberant pulse, thick skin, and large appetite. People with this constitution do not fall ill frequently, but when they do, they are susceptible to diseases of different kinds.

Yīn exuberance and yáng vacuity: Fleshy body, white complexion, tender skin, loose flesh, large and weak pulse, large appetite, and copious phlegm-drool.

Weakness of both yīn and yáng: Thin body, weak pulse, and poor appetite. A person with this kind of constitution tends to be frequently affected by minor ailments.

Fivefold Yīn-Yáng Classification

The fivefold yīn-yáng method of classifying constitutions originates in the Líng Shū (Chapter 72). This scheme is largely based on personality traits and on bearing and posture. It is concerned with the influence of constitution on the choice of needling treatment. The five classes are greater yīn (tài yīn), lesser yīn (shào yīn), greater yáng (tài yáng), lesser yáng (shào yáng), and yīn-yáng harmony. Each is associated with different degrees of yīn and yáng. Greater yīn (tài yīn) and greater yáng (tài yáng) are highly blemished personalities. Lesser yīn (shào yīn) and lesser yáng (shào yáng) are less severely blemished. The yīn-yáng harmony constitution represents the perfect balance.

This scheme is not widely presented in modern basic theory textbooks. An obvious difficulty is that it focuses on personality rather than physical traits, which might require greater knowledge of the patient’s personality than might be apparent in a physician-patient encounter, quite apart from raising questions about correspondences between personality and physical constitution. Furthermore, the positive descriptions of the yīn-yang harmony constitution contrast strikingly with the negative descriptions of the other constitutions.

Greater yīn (tài yīn)

Mostly yīn and no (very little) yáng. People with a greater yīn (tài yīn) constitution are greedy, malicious, and treacherous.

• They are acquisitive and avaricious, only concerned for personal gain.
• They are malicious and callous; they often plot to harm others to their own benefit.
• They do not show their true emotions; they are given to false modesty, hypocrisy, and treachery.
• They have a dark complexion.
• They tend to be tall, but often assume a bent posture.

Lesser yīn (shào yīn)

Mostly yīn and little yáng. People with a lesser yīn (shào yīn) constitution are small-hearted.

• They are concerned with petty gains.
• They gloat over the misfortunes of others and resent their good luck; they are jealous and ungrateful.
• They present a noble and upright air but are sneaky and devious.
• They tend to be fidgety.

Greater yáng (tài yáng)

Mostly yáng and no (very little) yīn. People with a greater yáng (tài yáng) constitution are overconfident, self-assertive, and unconscientious.

• They brag a lot but have little practical ability; they are complacent and do not brood over their failures.
• They are ostentatious, given to big talk, and tend to aim too high.
• They are sloppy and careless. While they like to give the impression of being magnanimous, they lack moral rectitude.
• They are often swayed by personal feelings. Their bearing and posture show their overconfidence.

Lesser yáng (shào yáng)

Mostly yáng and little yīn. People with a lesser yáng (shào yáng) constitution are self-respecting, competent, and attention-seeking.

• Their self-respect makes them competent in their work. They can be very proud of a lowly position.
• Although they are focused and careful in their work, they do not like to bury themselves in work without attracting public attention.
• Their bearing and posture reflect their confidence and self-respect.

Yīn-Yáng Harmony

People with a constitution characterized by yīn-yáng harmony are virtuous in every respect. They are what the Chinese call a jūn zǐ, the perfect gentleman.

• They are calm and composed; they do not easily get flustered.
• They have a sense of security and few fears.
• They are modest in their desires and are not given to excessive joy.
• They are honest, forthright, rational, and impartial.
• They are prudent, circumspect, yet adaptable. While their behavior is always principled, they go with the flow and are good at varying their actions according to the needs of any given situation.
• They tend to be dignified and serious but are warm-hearted and concerned for the welfare of others.
• If they hold a high position, they are modest and magnanimous. If they hold a low position, they are dutiful and not resentful of others.
• Their posture and bearing reflect calmness and confidence.

Five-Phase Classification

The fivefold method of classifying constitutions based on the five phases originates in the Líng Shū (Chapter 64). It is largely based on physical features and on adaptability to the seasons.

This scheme has been widely presented in the English literature and developed by some writers. However, it is not broadly used in China and is not usually presented in standard modern basic theory textbooks.

Wood Constitution

People with a wood constitution have a somber complexion, small head, long face, broad shoulders, straight back, small weak body, and agile limbs. They are talented, tend to work with their head, but lack physical stamina. They are assiduous in their work and tend to anxiety and preoccupation. They are more adjusted to spring and summer than to autumn and winter and tend to be susceptible to illness in cold weather.

Fire Constitution

People with a fire constitution have reddish skin. They have a broad, fleshy back, a small head with a thin pointed face, and small hands and feet. Their back and shoulders move when they walk. They have a lively intelligent mind. They lack confidence and tend to anxiety and impatience. They are knowledgeable and appreciate beauty. They often live to ripe age and die suddenly. They thrive better in spring and summer than in autumn and winter, tending to fall ill in cold weather.

Earth Constitution

People who have an earth constitution have a yellowish skin, a large head with a round face, fleshy shoulders and back, large abdomen, stocky legs, relatively small hands and feet, a symmetrical body, and a firm but light gait. Their mind is calm. They are outgoing and take pleasure in helping people. They do not like to use power and influence. The earth constitution thrives better in autumn and winter than in spring and summer and is susceptible to warm-heat qì in the spring and summer.

Metal Constitution

People who have a metal constitution have a square face and white skin. Their head, shoulders and back, abdomen, and hands and feet are small. Their heels are large and firm. Metal people are honest and upright. Although they tend to be rash and impatient, they are firm, resolute, and agile in their dealings. They thrive better in the autumn and winter than in the spring and summer and are susceptible to warm-heat qì in the spring and summer.

Water Constitution

People who have a water constitution have a blackish complexion, a large head with thin cheeks, narrow shoulders, a long back, a large abdomen, and nimble limbs that sway when they walk. They are fearless and tend to be dishonest and cruel. They thrive better in the autumn and winter than in the spring and summer and are susceptible to warm-heat qì in the spring and summer.

Modern Sixfold Classification

Scholars in China over recent years have tried to develop new schemes for classifying constitution. Most notable is the sixfold scheme contained in Zhōng Yī Tǐ Zhì Bìng Lǐ Xué (中医体质病理学 Constitutional Pathology of Tradition Chinese Medicine) by Kuāng Tiáo-Yuán (匡调元), 1996 (Shànghǎi Science and Technology Press). This scheme is influenced by the eight-principle and the qì, blood, and fluids pattern identification schemes. It therefore constitutes a refinement of the threefold yīn-yáng classification rooted in general modern diagnostic theory.

The advantages of this scheme are that it is based on broad research and avoids the excessive simplicity of the threefold yīn-yáng scheme described above. However, it is to be noted that neither this scheme nor any similar modern model has been generally acknowledged and adopted in the basic theory textbooks, suggesting that the question of constitution is still controversial.

Normal Constitution

This the same as the normal constitution in the threefold yīn-yáng scheme described above.

Slow and Cold Constitution

This constitution is characterized by insufficiency of original yáng and is treated by supplementing yáng and dispelling cold.

Yáng qì powers the activity of the body and provides the body with warmth. When yáng qì is insufficient, the signs observed are white flabby body, tendency to avoid physical exertion, lusterless complexion, physical cold and fear of cold, pale lips, harmony of mouth (i.e., no particular taste in the mouth), cold limbs, cold skin, a liking for hot drinks, spontaneous sweating, sloppy stool, long voidings of clear urine, a tendency to lose body hair, and tinnitus and deafness. The tongue is enlarged with dental impressions. The pulse is sunken and forceless.

Dry and Red Constitution

This constitution is essentially marked by vacuity heat. It is treated by enriching yīn and clearing vacuity heat.

The clinical manifestations are emaciation, dry mouth and pharynx, internal heat tending to cause constipation, short voidings of yellow urine, thirst with intake of fluids and liking for cold drinks, heat in the five hearts, heart vexation, insomnia, and deafness and tinnitus. The tongue is red with little or no fur. The pulse is fine, stringlike, and rapid.

Fatigued and Bright Constitution

This constitution is essentially marked by dual vacuity of qì and blood, with qì vacuity as the root cause. It is treated by boosting qì and engendering the blood.

The typical clinical signs are a bright-white complexion, shortness of breath, laziness to speak, lack of strength, dizziness, heart palpitation, forgetfulness, sweating at the slightest exertion, feelings of sagging in the anus or uterus, tendency for the hands to turn numb, and scant menstruation with pale discharge. The tongue is pale. The pulse is fine, weak, and forceless.

Slimy and Stagnant Constitution

This constitution is characterized by dampness (and phlegm). It is treated by eliminating dampness and transforming stagnation.

The main clinical signs are fat body, glomus and fullness in the stomach duct and abdomen, sweet taste in the mouth, sticky sensation in the mouth, generalized heaviness, sloppy stool, thirst with low fluid intake, oppression in the chest, and dizziness. The tongue fur is slimy. The pulse is soggy or slippery.

Dark and Rough Constitution

This constitution is characterized by blood stagnation. It is treated by moving blood and dispersing stasis.

The typical clinical signs are dark, dull, stagnant-looking skin, dark-colored lips, dark rings around the eyes, incrusted skin, dark speckles and red threads on the skin, glomus and oppression. The tongue is green-blue or purple. The pulse is sunken, rough, and moderate.

Modern Ninefold Classification

A new ninefold classification describes constitutions that all, with the exception of the normal one, correspond to disease patterns in modern Chinese medicine. It was adopted as the national standard by the State Administration of Traditional Chinese Medicine (SATCM) in 2009.

Type A. Harmonious (Normal) Constitution

The normal healthy constitution is one in which yīn and yáng, qì and blood are in harmony. This is called a harmonious constitution (平和质 píng hé zhì). It is characterized by normal stature and bearing, a healthy moist facial complexion, and general vigor.

• Body: Firm and strong.
• Common manifestations: Moist complexion, thick glossy hair, bright eyes, bright moist nose, good sense of smell, moist red lips, high energy level without tendency to fatigue, tolerance of cold and heat, good ability to sleep, good appetite, normal urine and stool, pale-red tongue with thin white fur, and a pulse that is harmonious, moderate, and forceful.
• Psychological disposition: Easy-going and happy.
• Pathological tendencies: Little illness.

Type B. Qì Vacuity Constitution

This constitution is one of insufficiency of original qì with fatigue, shortness of breath, and spontaneous sweating.

• Body: Soft flabby flesh.
• Common manifestations: Faint low voice, shortness of breath, laziness to speak, tendency toward fatigue, lack of essence-spirit vigor, tendency to sweat, pale-red tongue, with dental impressions on the margins, and a pulse that is weak.
• Psychological disposition: Introverted and averse to taking risks.
• Pathological tendencies: Susceptibility to common cold and vulnerability to wind, cold, summerheat, and dampness; tendency toward prolapse of the organs; slow recovery after illness.

Type C. Yáng Vacuity Constitution

Insufficiency of yáng qì with vacuity cold signs such as fear of cold and lack of warmth in the extremities.

• Body: Soft flabby flesh.
• Common manifestations: Fear of cold; lack of warmth in the extremities; liking for warm food and drinks; lack of essence-spirit vigor; enlarged tender-soft tongue, and a pulse that is sunken and slow.
• Psychological disposition: Quiet and introverted.
• Pathological tendencies: Tendency to phlegm-rheum, swelling, distension, and diarrhea; when evils are contracted, they tend to develop with cold.

Type D. Yīn Vacuity Constitution

This constitution is one of insufficiency of yīn-humor, with vacuity heat signs such as dry mouth and throat, as well as heat in the palms and soles.

• Body: Thin.
• Common manifestations: Heat in the palms and soles (vexing heat in the five hearts); dry mouth and throat; slightly dry nose; liking for cold drinks; dry stool; red tongue with scant liquid.
• Psychological disposition: Impatient and agitated, extroverted, physically active and lively.
• Pathological tendencies: Susceptibility to vacuity taxation, seminal loss, insomnia; greater tolerance for cold than hot environments; susceptibility to summerheat, heat, and dryness evils. Evils tend to develop with heat.

Type E. Phlegm-Damp Constitution

The phlegm-damp constitution is characterized by obesity, large abdomen, sticky sensation in the mouth, slimy tongue fur.

• Body: Obesity with large flabby abdomen.
• Common manifestations: Greasy facial complexion, profuse sweating with sticky sweat; oppression in the chest; copious phlegm; sticky, slimy sensation in the mouth; liking for fatty and sweet sticky foods; a slimy tongue fur; a pulse that is slippery.
• Psychological disposition: Gentle, steady and reliable; forbearing.
• Pathological tendencies: Susceptibility to dispersion-thirst, wind stroke, and chest impediment. General intolerance of rainy and damp weather.

Type F. Damp-Heat Constitution

In this constitution, the habitual presence of damp-heat is characterized by grimy complexion with a greasy glow, bitter taste in the mouth, slimy yellow tongue fur.

• Body: Medium or thin.
• Common manifestations: Grimy complexion with a greasy glow; susceptibility to acne; bitter taste in the mouth; dry mouth; fatigued cumbersome body; sticky stagnant or dry bound stool; short voidings of yellow urine; susceptibility to scrotal dampness in males and to copious vaginal discharge in women; red tongue with sticky yellow fur; a pulse that is slippery and rapid.
• Psychological disposition: Vexation and agitation.
• Pathological tendencies: Sores; damp-heat jaundice; damp-heat strangury (heat strangury). General aversion to hot humid weather.

Type G. Blood Stasis Constitution

This constitution is marked by poor movement of blood with dull dark skin, and dull purple tongue.

• Body: Fat or thin.
• Common manifestations: Dull skin; excessive pigmentation; dull pale lips; dull dark complexion; dull tongue with stasis speckles sometimes enlarged vessels on the underside; and a pulse that is rough.
• Psychological disposition: Tendency to vexation and forgetfulness.
• Pathological tendencies: Blood stasis patterns (concretions and conglomerations; pain); lack of endurance for cold.

Type H. Depressed Qì Constitution

People with depressed qì dynamic constitution show signs such as spirit-affect depression and worry.

• Body: Most commonly thin.
• Common manifestations: Spirit-affect depression; emotional fragility; vexation and oppression; pale tongue; a thin white tongue fur; and a pulse that is stringlike.
• Psychological disposition: Introverted, unstable, sensitive, and anxious with difficulty adjusting to environment mentally and difficulty putting up with rainy weather.
• Pathological tendencies: Susceptibility to visceral agitation, plum-pit qì, hundred-union disease, and depression patterns.

Type I. Idiosyncratic Constitutions

Idiosyncratic constitutions are seen in people with congenital defects and diseases, including the following:

• Hereditary diseases such as hemophilia, color blindness, diabetes (dispersion-thirst), physical deformities.
• Diseases attributable to fetal transmission (conditions transmitted to the child during pregnancy) such as the five slownesses, five limpnesses, fetal feebleness (胎弱 taī ruo4), fire toxin, syphilis, hepatitis B, AIDS.
• Allergies: wheezing and panting; wheals; itchy throat; nasal congestion and sneezing.

Which Classification System is the Most Reliable?

Since multiple systems exist, students naturally wonder which is the most reliable. The systems can be judged by their objective and perceived usefulness in the context of modern orthodox Chinese medicine, namely (a) by the degree to which they reflect diagnostic theory (biased constitutions being diagnosable like illnesses), (b) by the extent to which have been elaborated since they were introduced; (c) by how popular they are in modern Chinese-language textbooks.

Threefold yīn-yáng classification: This is the simplest system. Firmly based in diagnostic principles, it is the one that most commonly appears in Chinese textbooks, and very often the only one they present.

Fourfold yīn-yáng classification of Líng Shu1 (Chapter 67, Using Needles): This is not well elaborated and is not firmly based in diagnostic theory; it is mostly concerned with the influence of constitution on obtaining qì. It is rarely discussed in modern textbooks.

The fivefold yīn-yáng classification of Líng Shu1 (Chapter 72) is largely based on personality traits and on bearing and posture and is concerned with the influence of constitution on choice of needling treatment.

The fivefold classification system based on the five phases, based on Líng Shu1 (Chapter 64): This not usually presented in modern Chinese textbooks, although it is mentioned more widely in modern literature. While it has been elaborated and popularized in the West, modern Chinese scholars apparently consider it less useful.

The modern sixfold classification: This is well elaborated and firmly based in diagnostic theory. It does not include psychological dispositions.

The modern ninefold classification has the merit of being based in modern diagnostic theory and correspondence to disease patterns. It reflects psychological dispositions as well as physical states. Although it has been accepted as the modern standard, it is yet to be reflected in the literature.

Overall, the Neì Jing1 schemes are not highly valued by modern Chinese scholars. This may be because they are based excessively on psychological disposition, on the five phases, the channel system, and relationship to needling.

The threefold yīn-yáng classification is widely accepted. However, since the modern sixfold and ninefold schemes incorporate it but further elaborate on it, it is apparently considered, in itself, to be too simplistic.

Modern Chinese TCM scholars seem to be leaning toward schemes based on insufficiency of yīn, yáng, qì, and blood, and on typically chronic conditions of superabundance related to these, notably qì stagnation, blood stasis, dampness, and phlegm. The latest, ninefold scheme reasserts a classical concern with psychological disposition and adaptability to seasons.

Formation of Constitution

An individual’s constitution is dependent upon numerous factors that can be broadly divided into earlier heaven (congenital) factors and later heaven (acquired) factors.

Earlier-Heaven Influences

Offspring are produced by the mingling of male and female essence. Their physical characteristics, such as height, build, and skin color stem from the parents. The same applies to psychological characteristics. In addition, the state of both parents reproductive essence at the time of conception affects the strength of the individual’s constitution. The state of the mother’s health during pregnancy is also influential. Traditionally, great importance is accorded to nurturing the fetus (养胎 yǎng tāi) before and during pregnancy—that is, following a set of guidelines to ensure a balanced diet, moderate exercise, good physical posture, cheerful mood, and avoidance of excessive cold or heat and sexual activity.

Later-Heaven Influences

Later-heaven influences include illness, stage in life, diet, activity and exercise, gender, emotional life, geography and climate, sex life, and work.

Illness

Patients with a strong constitution can quickly overcome minor illnesses. Major illness, however, can take a lasting toll on health. The resulting damage to qì, blood, fluids, yīn, or yáng may alter a patient’s constitution and make them more susceptible to particular evils. For example, a person with a yīn-biased (yáng vacuity) constitution of the slow and cold type may be more prone to dampness. Repeated dampness afflictions will be likely to weaken the constitution further and turn it into a slimy and stagnant constitution.

Illness is not necessarily the most important influences on constitution. However, many of the other factors described below exert their effects on constitution by causing illness.

Stage in Life

Constitution varies with age. Development and aging are explained in terms of essence in Chinese medicine. As essence increases in early life, the constitution becomes stronger. As it declines in later life, the constitution becomes weaker.

Childhood: In infancy and childhood, the bowels and viscera are still delicate, qì and blood are not fully developed, and yīn and yáng are still weak. Children are prone to both vacuity and repletion diseases, and to heat diseases as well as cold diseases. Their spirit qì is still very frail and so they are susceptible to fright. Powerful stimuli may not only disturb them emotionally; they can cause physical illness. Young children are also prone to high fever with convulsions, which is called fright wind. And lastly, they are susceptible to eruptive diseases like measles (and in the past smallpox).

Prime of life: As individuals progress through puberty into early adulthood, their physical constitution improves. Qì, blood, yīn, and yáng become stronger; the sinews and bones become tougher. At this point, the body reaches its prime of life, in terms of both physical and mental capacity. In the prime of life, illnesses tend to take the form of repletion rather than vacuity.

Advancing years: As people advance beyond the prime of life, their qì, blood, yīn, and yáng grow weaker; their bowel and visceral functions decline; their sinews and bones weaken; their bodies become less agile; their hearing and vision decline; and their reactions grow duller.

In advancing years, people suffer from fatigue, dizziness, constipation or diarrhea. Vacuity conditions are more common than in the prime of life. Many are directly related to the kidney––the root of the yīn and yáng of the entire body. Weak aching lumbus and knees, deafness, tinnitus, premature graying and hair loss, loosening of the teeth, and weakening of the bones are all observed in old age. At the same time, specific forms of vacuity-repletion complexes tend to develop. For example, liver-kidney yīn vacuity and ascendant hyperactivity of liver yáng is highly prevalent in later life. Many patients suffering from this condition are found to be hypertensive in modern medical terms. Since liver yáng can transform into wind, these people have a higher risk of wind strike (stroke).

In advancing years, the diseases to which people are prone are by no means all attributable to insufficiency. Weakness of right qì makes people susceptible to external evils. A typical example is the diabetic tendency to infections.

Diet

A regular and balanced diet is essential for the maintenance of health. Diet is conditioned by availability and affordability of foods, as well as preferences about them.

In conditions of poverty, an insufficiently nutritious diet may cause emaciation and weak health.

In conditions of affluence, people tend to suffer from overeating, an imbalanced diet, and the consumption of unhealthy foods. In such conditions, a healthy constitution is maintained by eating in moderation. The Chinese often say, eat eight tenths full. This means that not quite eating your fill is one way to stay healthy.

Health is maintained by a varied diet of simple and plain food that avoids any excesses. Chinese medicine traditionally recognizes the following excesses:

• Sweet and fatty foods in excess inevitably lead to exuberant physique and vacuous qì (形盛气虚 xíng shèn qì xū), that is, obesity with lack of vigor. Chinese medicine recognizes that obese persons are prone to phlegm diseases. So, excessive consumption of sweet and fatty foods fosters a constitution characterized by overweight and phlegm-damp.
• Salty foods in excess can damage the blood and heart, giving rise to a constitution characterized by heart vacuity.
• Warm- and hot-natured foods such as lamb or dog meat or hot acrid spicy food, when consumed over long periods, can foster a tendency to yīn vacuity with effulgent fire.
• Cold-natured foods such as green vegetables, especially when uncooked, can damage yáng qì. Physically cold foods like ice-cream and iced drinks are also considered damaging to yáng qì.
• Excessive consumption of alcohol, especially distilled liquor, encourages the development of damp-heat and damages the liver and spleen, as does smoking.
• According to modern ideas about nutrition, people generally tend to consume too much salt, sugar, and fat and do not consume enough vegetable matter. These ideas are largely in keeping with traditional Chinese medical notions of a good diet. The main difference is that Chinese medicine emphasizes avoiding excessive consumption of raw and cold foods, which modern nutritionists generally encourage.

Persistent dietary habits affect constitution. Attention to correct diet can improve a person’s constitution.

Activity

Human beings need adequate exercise to stay healthy. Physical activity exercises the flesh, sinews, and bones, and keeps the joints free. By promoting the flow of qì and blood, it also strengthens the function of the bowels and viscera and in particular stimulates digestion and assimilation. People who lead physically active lives tend to have strong sinews and bones with a healthy covering of flesh. With hearty appetites and robust constitutions, they do not easily fall sick. Too much and too little physical activity can be damaging.

Overactivity: People engaged in physical labor tend to generate heat in their bodies and therefore have a tendency toward yīn vacuity. People whose work confines them to a certain posture or forces them to overuse certain body parts can suffer damage to sinews and bones. Students and others who use their brainpower late into the night can easily develop yīn vacuity.

Underactivity: People who do not get enough exercise have weak sinews and bones. Even if they dont eat very much, they tend to suffer from obesity, have weak constitutions, and be prone to illness. Sù Wèn (Chapter 23) states, Prolonged vision damages the blood; prolonged lying damages qì, prolonged sitting damages the flesh; prolonged standing damages the bones; and prolonged walking damages the sinews. These are the five taxations, three of which are the result of inactivity.

In the modern world, increasing numbers of people have sedentary occupations, rely on motorized transportation, and use brainpower rather than physical strength. When such people do not exercise, they may be prone to poor health.

We should also remember that diet and exercise interact. Modern civilization poses a dangerous conjugation of an over-rich diet and lack of exercise.

Exercise

Physical exercise is specific activities designed to increase bodily strength and agility and enhance both physical and mental well-being. It has been cultivated in Chinese culture, as in the West, since ancient times.

Exercise is often integrated into sports, which serve additional purposes such as entertainment and satisfaction of the competitive spirit. The competitivity of sport often has a negative impact on the quality of the exercise it provides, since it encourages excessively strenuous exercise for excessively long periods or exercise of a negative kind. Certain sports also pose the danger of physical injury, such as sprained ankles in basketball players and epicondylitis in tennis players. In general, Chinese sports and systems of exercise are less damaging than their Western counterparts.

The famous legendary doctor Hua2 Tuo2 supposedly said, The human body requires taxing movement (i.e., physical exercise), but it should not be carried to extremes. He believed that exercise was beneficial to health by its ability to promote the flow of qì and blood and to enhance digestion. Hua2 Tuo2 is credited with inventing the five animal exercises, a system of exercises that imitate the movements of animals. Since Hua2 Tuo2’s time, numerous styles of qì-gong1 and martial arts have developed in China, all of which have the purpose of enhancing human health.

Qì-gong1 includes many different schools of practice, but they all aim to enhance essence, qì, and the spirit. The term qì-gong1 literally means qì work. Through continual practice, adepts can strengthen their essence to enhance its ability to form qì, which in turn produces spirit. The spirit can in turn control qì, so that qì can produce essence. Essence, qì, and spirit, referred to generically as the Three Treasures, are extremely important in all Chinese life-nurturing practices.

Martial arts, which like qì-gong1, come in many shapes and forms, are methods for developing powers of self-defense and enhancing health. They strengthen sinews and bones, promote agility, and enhance alertness and reaction speed.

Gender

Male is yáng and female is yīn. According to the associations of yīn and yáng in the theory of correspondences, this means that men are physically larger and stronger than females; have a greater capacity for physical labor, and many spend their lives engaged in it. Furthermore, they tend to be more assertive and aggressive in their nature. Women have smaller, less powerful bodies, and are less physically active: they tend to be gentler and quieter in nature and more sensitive than males. These statements are, of course, generalizations, and they apply less in modern societies where gender roles are changing.

Women’s reproductive functions have a significant bearing on their constitution. Menstruation and childbirth involve blood loss. The nurturing of the fetus and newborn taxes the qì and blood of the mother. The liver is especially important in women; they are said to have the liver as their earlier heaven. This means that although the kidney is normally understood to be most closely associated with earlier-heaven (congenital) factors in both men and women because it stores earlier-heaven essence, in women the liver is almost as important as the kidney because of its importance in reproductive functions. Women are especially susceptible to certain qì and blood problems, such as blood vacuity stemming from excessive loss of blood via the vagina, which may be the result of qì vacuity (spleen failing to control the blood). They are also susceptible to menstrual problems arising from depressed liver qì. In this respect, women tend to have weaker constitutions than males. Nevertheless, as research has demonstrated, women generally have a longer life span than males and are less prone to life threatening diseases (respiratory tract infections, viral infections of the central nervous system, gastrointestinal viruses, and hepatitis).

Sex Life

Chinese medicine recognizes that sexual activity is not only required for procreation but also for maintaining physical and mental health. A traditional Chinese saying states, When males reach adulthood, they should take a wife; when females reach adulthood, they should take a husband. In traditional Chinese culture, the socially recognized purpose of marriage was to give one’s parents grandchildren and to keep the family line going. Yet it was also tacitly recognized that sexual activity was important and that it was abnormal and unhealthy not to have a sex life. In the Chinese medical view, sexual satisfaction helps to keep a person happy, and the absence of sexual activity can create mental depression, which in turn causes qì and blood to become depressed and stagnant.

While recognizing sex as being necessary and natural, Chinese medicine strongly warns against excessive indulgence on the grounds that it damages essential qì and shortens life. This is considered especially true of males, who can lose large amounts of essence through over-frequent ejaculation.

In women, the loss of essence through intercourse is seen as less severe than the burden placed on the body by the reproductive processes, namely the nurturance of the fetus during pregnancy, the loss of blood through childbirth, and the continuing drain on the mother’s resources during lactation.

Emotional Life

Occasional emotional stimulus causes immediate changes within the body, which are usually transient. Severe and lasting emotional stimulus, however, can have a damaging effect on the body by causing imbalances and disturbances of qì, blood, yīn, and yáng. Intense preoccupation or work stress, conflicts with others that create anger and frustration, failure to find a sexual partner or achieve career goals, and loss of family members, friends, or pets are some emotional factors that perennially threaten our health. Unvented anger and a tendency to rashness and impatience can foster a liver-fire constitution. Persistent anxiety and worry can cause a patient to become oppressed and have little enjoyment of life, giving rise to a depressed liver constitution.

Geography and Climate

Different geographical areas have different climates.

In China, the south tends to be hot and humid, the north cold and dry. The east has a gentle climate, and the west and north have deserts, high plateaus, and river valleys. These differences create a varied continental climate, which has caused differences in the constitutions of the people. The northern Chinese are physically larger and stronger than the southerners. According to traditional theory, a harsh climate makes people tougher and more aggressive, while a gentle climate makes people physically more delicate and less aggressive.

Inland areas to tend to be dry, while coastal areas tend to be damp. In damp regions, impediment disease (bì) is more prevalent than in dry areas. Fishery workers in coastal regions are prone to dampness diseases. In hot and humid areas, malarial disease may be prevalent. The prevalence of disease can affect constitution.

Work

Work is closely related to illness, activity and exercise, diet, and emotional life, since the type of work a person does often makes people prone to certain illnesses, determines how much exercise a person gets, affects how a person eats, and affects what kind of emotional factors may operant in a person’s life. In short, it affects all the long-lasting influences that may affect a person’s constitution. Furthermore, geography and climate, as well as gender, can influence what work a person does.

• A low-level sedentary occupation can be boring and allow little opportunity for exercise.
• A sedentary occupation that requires brainwork may lead to excessive thought and preoccupation.
• Using computers, cell phones and energy-efficient lighting (e.g., LED), especially after sundown, increases exposure to blue light, which can affect our ability to sleep and upset our circadian rhythms. The effects of blue light are still not fully understood.
• A high-level management job might involve insufficient exercise and usually brings stress and frustration.
• Stress, frustration, and resentment are generally felt in working environments where there is constant pressure for greater efficiency.
• Heavy manual labor often causes repeated damage to the flesh, sinew, and bone. This in turn damages the viscera governing these body constituents, as well as qì and blood.
• Musicians, tennis players, sportspeople, and people of many other occupations are prone to specific forms of damage to flesh, sinew, bone, and in some cases the eyes and ears.
• People who work in excessively damp, dry, or toxic environments are prone to various specific diseases.
• Almost every occupation harbors physical or emotional dangers that can damage the health. Since the damage is often chronic, it easily causes illness and eventually reaps its toll on the constitution.

Application of Constitution Theory

Constitution and Causes of Disease

Constitution determines susceptibility to particular causes of disease. Different constitutions are especially vulnerable to certain diseases. This is because similar qì seek each other.

• People with yīn-biased constitutions habitually suffer from yáng vacuity that manifests in physical cold and fear of cold. They are susceptible to cold evil that gives rise to cold diseases. When they contract cold evil, it tends to enter the interior and damage the yáng qì of the spleen and kidney.
• People with yáng-biased constitutions, characterized by a dry-red complexion, cannot tolerate the heat of summer and tend to contract warm evils.
• In people who habitually have exuberant dampness and easily contract dampness evil, there is a tendency for external dampness to induce or exacerbate internal dampness, causing diarrhea and water swelling.
• Obese people tend to have copious phlegm-damp and are susceptible to wind stroke.
• Thin people tend to have copious fire and are susceptible to consumption cough.
• The elderly have debilitated kidneys and are susceptible to phlegm-rheum cough and panting.

Constitution and Pathomechanisms

Constitution influences whether a person falls ill, what diseases they are prone to, how a disease develops once it has begun its course, and whether or not relapses will occur.

Constitution and pathogenesis: Right qì vacuity is the intrinsic cause of disease, while evil qì is its extrinsic cause. For evil to settle in the body, there must be some degree of right qì vacuity. When right qì is vacuous, evils can exploit the vacuity and enter. When right qì is replete, it is difficult for evil to get in. The strength of right qì is determined by constitution.

• Constitutional imbalances: When, for example, people who habitually suffer from spleen yáng vacuity eat raw and cold foodstuffs, they easily suffer from diarrhea. By contrast, people with healthy spleens can eat raw and cold foods without suffering from diarrhea.
• Constitution-determined reactions to evils: Different constitutions can react differently to one and the same disease evil. For example, when a person with a strong constitution contracts external cold, it is likely to manifest as a wind-cold exterior pattern with heat effusion, aversion to cold, headache and generalized pain, a thin tongue fur, and a floating pulse. Someone with a yáng-vacuity constitution, in whom right qì is unable to overcome the evil, will be more severely affected. The cold evil is likely to directly strike the stomach and spleen, giving rise to fear of cold, cold limbs, torpid intake (a tendency to eat less because eating causes fullness), reduced eating, abdominal pain, diarrhea, and a pulse that is moderate and weak.

Constitutionally influenced transformation: In Chinese medicine, the way in which an illness develops depends on the individual’s constitution. This is called constitutionally influenced transformation (质化 zhì hua4).

After contraction of external evils, the progression of disease varies according to the constitution of the patient.

• Externally contracted wind-cold evil in patients with a yáng-biased constitution tends to transform into heat under the influence of yáng. In people with a yīn-biased constitution, it tends to transform into cold under the influence of yīn.
• Externally contracted damp evil in a patient with a yáng-hot constitution will develop with heat under the influence of yáng, giving rise to a damp-heat pattern. In a patient with a yīn-cold constitution, it develops with cold under the influence of yīn, giving rise to a cold-damp pattern.

Constitution and disease shifts: The shifts in the course of the development of a disease depend greatly on the patient’s constitution. The course of a disease is not immutably fixed; much depends on the individual. When the patient is strong and evil is weak, right qì fights the evil, so that the patient recovers. In externally contracted disease, the progression of the disease evil through different channels or aspects depends on the strength of the patient’s constitution. For example, as the Shang1 Han2 Lun4 tells us, in a patient who has been sick with greater yáng (taì yáng) disease for seven days or more, if right qì is strong, it can overcome the evil; if it is not strong, the disease can shift from the yáng to the yīn channels.

Constitution and Treatment

Chinese medicine knows a treatment principle called action according to time, place, and person. This means that treatment varies according to the time of year, the locality, and the needs of the individual. Action according to person means specifically that the physician should vary the treatment depending on the constitution of the individual patient. In clinical practice, when one and the same illness is treated in the same way in different patients, the results are different. A treatment that is successful for one patient may be unsuccessful or even harmful to another. Constitution has great bearing on treatment, because it can determine how effective it is.

Action according to person: Different constitutions require different treatments.

Build: Obese people with a white complexion (white flabby type) have a cold-damp constitution. If they contract cold-damp evil, they therefore have to be treated with warm-hot medicines such as gan1 jiang1 (Zingiberis Rhizoma), fù zi3 (Aconiti Radix Lateralis Praeparata), and ren2 shen1 (Ginseng Radix) in order to expel the evil. If they contract damp-heat, it is likely to be persistent. The treatment must center on freeing yáng to transform dampness. In such patients, cold- or cool-natured medicinals cannot be used excessively because they obstruct the dampness and weaken yáng qì even further.

Emaciated patients with a somber complexion have a yīn-vacuity constitution and tend to suffer from stirring of internal fire. When such a patient contracts dampness, the dampness will develop under the influence of the heat. Such a patient suffers not only from damp-heat but also from damage to liquid. Hence, dampness develops in vastly different ways in people of different constitutions. This makes a big difference in the choice of treatment.

Age: Since age is an important factor in determining constitution, it is therefore of great significance when choosing appropriate treatment. Qì, blood, yīn, and yáng, and the bowels and viscera vary in strength according to age.

In young children, yīn and yáng are still frail. Whether one uses warm-hot medicinals or bitter-cold medicinals, it is important to discontinue the treatment as soon as the disease has been struck.

The elderly tend to suffer from chronic vacuity conditions, such as kidney debilitation. They easily contract evils and fall ill; even externally contracted illness will tend to take the form of vacuity or vacuity-repletion complexes. In treatment, therefore, the practitioner must protect yīn and yáng and avoid harsh offensive treatments, even when addressing evil repletion.

Gender: Gender is a significant aspect for determining treatment. In women, the liver is especially important, and so it is said that women have the liver as their earlier heaven. They are susceptible to liver depression and to blood vacuity. When treating women, it is important to take these conditions into account.

Unlike treatment of like disease; like treatment of unlike disease: In Chinese medicine, the practitioner addresses the patient rather than the patient’s disease. Because of differences in constitution, a similar illness (similar disease pattern) appearing in different people may be treated in different ways. Similarly, different diseases occurring in the same patient are influenced by the patient’s constitution and may for this reason produce similar signs. Hence, they call for similar treatment.

Use of medicinals: Generally speaking, when treating patients with yáng-biased constitutions, the practitioner should use medicinals that are sweet and cold, sour and cold, and clearing and moistening, while avoiding the use of acrid and hot, warm and dispersing medicinals. When treating patients with yīn-biased constitutions, it is appropriate to use warming and supplementing, fire-boosting medicines and not to use cold bitter downsinking fire-discharging medicinals. Patients with qì vacuity constitutions should be given qì-supplementing medicinals.

Dosage: Large, heavy individuals need larger doses than emaciated and weak patients. Rash and impatient people need larger doses than the wary and circumspect.

Adjustive treatment after illness: A practitioner of traditional Chinese medicine continues treatment even after the patient recovers from the illness itself, to restore the patient to full health. This treatment can include medicinal therapy, diet therapy, and general counseling. In this context, constitution plays a great role. People with yáng-biased constitutions in China are advised not to eat too much dog meat, lamb, or dried longans because of their warm nature. People with yīn-biased constitutions are advised not to each too much rich meat like tortoise or turtle meat or astringent items such as wu3 weì zi3 (Schisandrae Fructus) and wū mei2 (Mume Fructus).